Donald Tusk, European Council President, on Thursday said May's idea that the UK could stay in the single market for goods after Brexit "will not work," and had been rejected by leaders of all 27 EU member states.

He was joined by French president Emmanuel Macron, who dismissed the entire Brexit project as being pursued by "liars".

It was a humiliating day for May, who had travelled to Salzburg, Austria quietly confident of receiving encouraging feedback on her Chequers proposals, after recent reports suggested Brussels was ready to soften its Brexit position.

Michel Barnier, the bloc's chief Brexit negotiator, said on numerous occasions this summer that its core proposals — the UK effectively stays in the single market for goods and collects EU tariffs on Brussel's behalf — were never going to be accepted.

It certainly was not prepared for French President Emmanuel Macron to describe Brexit-supporting politicians as "liars" in a pretty extraordinary press conference.